1. Field of the Invention
The present invention relates to a contact and a method for manufacturing the contact. In particular, the present invention relates to a contact suitable for use in electrical connection to a semiconductor device having bumps (protrusion electrodes) formed into the shape of a sphere or a land, as well as a method for manufacturing the contact.
2. Description of the Related Art
In general, in a manufacturing process of a semiconductor device, e.g., an integrated circuit (IC) or large scale integration (LSI: IC in which the degree of integration of elements is 1,000 to 10,000), a produced semiconductor device is connected to an inspection wiring board called a probe card and thereby, the semiconductor device is subjected to an electric signal input/output inspection. Consequently, an expense in time and effort for incorporating a defective semiconductor device into a package is reduced.
In a prove card for inspecting a semiconductor device of ball grid array (BGA) system or a semiconductor device of land grid array system, an inspection wiring for passing an electric signal is disposed on the substrate and, in addition, conical contacts having an outer diameter of a few tens of micrometers and having a center portion serving as a top portion are connected to connection terminals of the inspection wiring disposed at a narrow pitch of a few tens of micrometers, so as to be connected to a plurality of spherical bumps (protrusion electrodes) disposed at a narrow pitch of a few tens of micrometers on the semiconductor device or land-shaped bumps having a width of a few tens of micrometers.
This known contact is formed by patterning a conical spiral metal film through the use of an organic resist material and plating a metal, e.g., Cu and Au, having good electrical conductivity on the surface of the metal film.
However, the electric signal input/output inspection of the semiconductor device is a burn-in test in which the temperature (about 120° C.) is higher than the usual working temperature of the semiconductor device and a voltage higher than the usual working voltage is supplied. Therefore, when the burn-in test is repeated, slip deformation which becomes a cause of permanent deformation tends to occur. Consequently, there is a problem in that the permanent set in the shape of the contact occurs in a direction in which an appropriate pressure is not applied to the bump.
Here, it is thought that good properties will be exhibited by using a shape memory alloy having excellent shape recovery property and excellent heat resistance as the contact. However, the shape memory alloy cannot be formed by plating. Although a shape memory alloy film can be formed by sputtering the shape memory alloy, when etching is performed to obtain a desired shape after the sputtering is performed, since the etching resistance of the material for the contact is low with respect to the etching solution of the shape memory alloy, there is a disadvantage that the contact is also removed by etching during the etching of the shape memory alloy. Furthermore, when lift-off by using a resist is intended, sputtering and a heat treatment of the shape memory alloy must be performed under a high temperature environment at about 200° C. to 500° C. Consequently, even when patterning is performed by using an organic resist material, a contact having a desired shape cannot be obtained because the organic resist material cannot endure the high temperature environment.